If so, the aviation start-up Terrafugia is willfully disregarding it. Last week, the Woburn company unveiled a concept design for a product called the TF-X — well before it has delivered its first product, the Transition “roadable aircraft.”

But Terrafugia’s chief executive, Carl Dietrich, says the TF-X could — a big could here — usher flying cars into the mainstream. It could take off and land vertically, outside of an airport. (Heliports or empty lots are fair game, as long as you have permission.)

It would have “fly-by-wire” controls that would let you set your destination, and the vehicle would navigate to it with minimal pilot involvement. It would be a plug-in hybrid, presumably making it more fuel-efficient than most private aircraft, with a 500-mile range.

And as with the Transition, if you encounter bad weather, you simply land at the nearest safe spot and drive the rest of the way.

If Terrafugia can attain large enough production volumes, the TF-X might be a flying car the middle class (OK, upper-middle class) could afford. (Terrafugia anticipates a $279,000 base price; Dietrich expressed hopes the TF-X would sell for less than that.) Dietrich acknowledges that getting the TF-X to market will probably be an eight- to 10-year process and require some major fund-raising.

Co-working redefined

I stopped by the future home of Workbar in Central Square in Cambridge last week to see the construction progress. The shared office space is scheduled to open by May 20, founder Bill Jacobson says. It will be the second Workbar location; the first is near South Station in Boston.

Workbar offers memberships for as low as $30 for a day pass and up to $2,400 per month for a four-person private office. There are shared kitchens, copiers, and printers, as well as high-speed Internet access.

The Cambridge location, on Prospect Street about a block from the Central Square MBTA station, will be more visible than Workbar Boston, which is below street level. Cambridge has what Jacobson calls a “business-centric café space” at street level, with cushy sofas, shared tables, whiteboards, a coffee bar, and digital signs that will display who is in the office at the time, as well as upcoming events. A “welcomista” will greet prospective members and show them around. On the mezzanine level, a glass-walled room can be used for training sessions or private meetings. (The first-floor space used to house Crimson Hexagon, a social media monitoring start-up that moved to Boston.)

Workbar also has the top floor, which Jacobson has carved up into three sections. The Study is for quiet “heads-down work.” It has views of the Boston skyline. The Commons is an open area for teams working together. In the back is The Switchboard, where it’s OK to make phone calls or conduct Skype video chats. (There are also private booths for phone calls and an area that will house a few treadmill workstations.) The top floor also has two small outdoor patios and a kitchen with a communal table.

As at the Boston location, Jacobson expects the denizens of Workbar Cambridge to be a mix of consultants, freelancers, early-stage companies, and individuals or teams from bigger companies who may not yet have local offices.

Jacobson says the first and fifth floor spaces are about 13,000 square feet. Analogue Studio of Boston worked on the interior design and Anderson Porter of Cambridge was the architect.